A normally unmanned installation offshore is a type of automated oil or gas platform designed to be primarily remotely operated, without the constant presence of personnel.
These platforms are generally characterized by their small size. They are often a compromise between providing the convenience of surface wellheads, which are easier to build and maintain and avoiding the high operating cost of a full production platform.
The unmanned platforms are commonly serviced from a nearby larger platform. Regular visit may be made for routine maintenance and for smaller well work, such as wireline operation by for instance a service operation vessel.
Even though the platforms are small and most of the time unmanned there is a requirement for equipment that fulfills the safety regulations when the platform is manned. The reduced space also requires other solutions than normal platforms.
The platforms are considered to be in an environment with a potentially explosive atmosphere due to the presence of gases, vapor, mist or dust. An ignition may cause an explosion in these environments. To avoid this there is strictly requirements to which equipment that can be used directly in the explosive atmosphere.
The overall design philosophy for the unmanned platform is to minimize the equipment on the platform, thus minimizing the requirement for visiting the platform to operation and maintenance. Planned visits to the platform could be limited to once a year except for unplanned well maintenance. Further, focus is on efficient and safe evacuation if for some reason a leakage and/or fire should occur during a visit.
Due to the operation of these platforms, there are needs for new equipment that are adapted for these specific platform types.
A deck hoist tractor is proposed to handle materials on weather deck and between decks during the drilling phase with the presence of a jack up rig. This is a newly developed concept but devices with similar functionality have been used before on offshore installations. One example is the offshore oil installation Ringhornet.
The deck hoist tractor is required to meet the requirements in the ATEX directive regarding minimizing explosion. This deck tractor is therefore powered on the unmanned wellhead platform by supply from the jack up rig or main installation umbilical.
The deck hoist tractor provides material handling of different loads that are performed by precise and safe lifting operations on offshore installations.
The publication AU61466 relates to a material handling system and means for unloading material from a vehicle and transporting the material to a desired location, the handling system is preferable used in a construction site and not on an offshore platform as the deck hoist tractor according to the invention. The publication comprises a lower frame that supports belts for movement of the system but do not describe any possibility for precise positioning of a load to be hoisted.
Publication U.S. Pat. No. 5,090,667 and DE102010005875 discloses technical background of the invention.
None of the publications describes a hoist tractor that could be used on a platform that fulfills the safety regulations set for the platform and at the same time could perform installation lift in demanding atmosphere safely and with precision.
An escape chute represents an emergency evacuation system that is designed to provide rapid means of escape.
An escape chute shall be installed during all visits on the unmanned wellhead platform. The invention allows for that this installation could be performed by the crane on a service operation vessel that are connected to the platform during for instance maintenance of the platform.
A tote tank could have many purposes in the industry. A tote tank is normally a standardized tank with a load carrier and protection that are integrated in the tank.
Publication US2005/0098559 relates to a tote tank for transporting dangerous liquids between the dock and the offshore platform.
Publication 2633332 discloses another example of a traditional tote tank for storing liquids at various work sites.
The tote tanks in the publication are adapted to be arranged on a deck, vessel or other work sites.
The unmanned platform has however a constricted area where the tote tank may be installed by a crane and which at the same time is low enough to allow fluid to flow into the tank.
The invention solves this problem by providing a method for installing and connecting a tote tank in an unmanned platform by arranging the tote tank in a recess in the landing platform or directly on the platform.